Base station and wireless communication method

ABSTRACT

In a base station, wireless communication method, and wireless communication system, a base station belonging to a first communication system shares the same frequency band with a second wireless communication system. The bandwidth of the first system has at least 5 MHz and 1.4 MHz, a plurality of carriers is available for the 1.4 MHz and a single carrier is available for the 5 MHz in the first system, and a communication scheme of the first system uses a time division duplex long term evolution (TD-LTE). A communication scheme of the second system is different from the TD-LTE, and the base station enables a wireless communication using either 1.4 MHz bandwidth or 5 MHz bandwidth of the first system according to a status of use of the shared frequency band by the second system.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.15/751,195, filed Feb. 8, 2018, which is a continuation based on PCTApplication No. PCT/JP2016/072986, filed on Aug. 4, 2016, which claimsthe benefit of Japanese Patent Application No. 2015-158698, filed onAug. 11, 2015. The content of which is incorporated by reference hereinin their entirety.

TECHNICAL FIELD

The present disclosure relates to a base station that performs wirelesscommunication and a wireless communication method.

BACKGROUND ART

As a frequency band of PHS (Personal Handy-phone System), 1884.5 MHz to1915.7 MHz are allocated. In the frequency band, 1893.5 MHz to 1906.1MHz are a common band for public and private use. In the common band,public PHS, private PHS, DECT (Digital Enhanced CordlessTelecommunications) and the like are available.

In future, in the common band, it is expected to use an XGP (eXtendedGlobal Platform) wireless communication method that realizes M2M(Machine-to-Machine), IoT (Internet of Things) and the like, and a highquality communication service of high speed, low delay and the like isconsidered.

For example, in a TD-LTE (Time Division duplex-Long Term Evolution)wireless communication method used in the XGP method, a carrier used intransmission may take frequency bandwidths (hereinafter, referred to asbandwidths) of 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, and 20 MHz (Non-PatentLiteratures 1 and 2, and the like). The number of resource blocks (RBs)included in each bandwidth is 6 RBs, 15 RBs, 25 RBs, 50 RBs, and 100RBs, respectively, and the communication speed becomes fast as thebandwidth is widened.

CITATION LIST Non-Patent Literature

-   Non-Patent Literature 1: 3GPP TS 36.101 Ver. 9.0.0 “LTE; Evolved    Universal Terrestrial Radio Access (U-UTRA); User Equipment (UE)    radio transmission and reception”-   Non-Patent Literature 2: 3GPP TS 36.211 Ver. 9.0.0 “LTE; Evolved    Universal Terrestrial Radio Access (U-UTRA); Physical channels and    modulation”

SUMMARY

A base station according to the present disclosure belongs to a firstwireless communication system and comprises a controller configured toshare the same frequency band with a second wireless communicationsystem, and to use a time division duplex long term evolution (TD-LTE)as a communication scheme of the first wireless communication system. Acommunication scheme of the second wireless communication system isdifferent from the TD-LTE, the bandwidth of the first wirelesscommunication system has at least 5 MHz and 1.4 MHz, and a plurality ofcarriers is available for the 1.4 MHz and a single carrier is availablefor the 5 MHz in the first wireless communication system. The controlleris further configured to enable a wireless communication using 1.4 MHzbandwidth of the first wireless communication system, according to astatus of use of the shared frequency band by the second wirelesscommunication system.

A wireless communication method according to the present disclosure isperformed at a base station belonging to a first wireless communicationsystem and comprises sharing the same frequency band with a secondwireless communication system, wherein the bandwidth of the firstwireless communication system has at least 5 MHz and 1.4 MHz, and aplurality of carriers is available for the 1.4 MHz and a single carrieris available for the 5 MHz in the first wireless communication system,using a time division duplex long term evolution (TD-LTE) as acommunication scheme of the first wireless communication system, whereina communication scheme of the second wireless communication system isdifferent from the TD-LTE, and enabling a wireless communication using1.4 MHz bandwidth of the first wireless communication system, accordingto a status of use of the shared frequency band by the second wirelesscommunication system.

A first wireless communication system according to the presentdisclosure comprises a base station configured to share the samefrequency band with a second wireless communication system, wherein thebandwidth of the first wireless communication system has at least 5 MHzand 1.4 MHz, and a plurality of carriers is available for the 1.4 MHzand a single carrier is available for the 5 MHz in the first wirelesscommunication system, use a time division duplex long term evolution(TD-LTE) as a communication scheme of the first wireless communicationsystem, wherein a communication scheme of the second wirelesscommunication system is different from the TD-LTE, and enable a wirelesscommunication using 1.4 MHz bandwidth of the first wirelesscommunication system, according to a status of use of the sharedfrequency band by the second wireless communication system.

A wireless communication method according to the present disclosure isperformed at a base station belonging to a first wireless communicationsystem and comprises sharing the same frequency band with a secondwireless communication system, wherein the bandwidth of the firstwireless communication system has at least 5 MHz and 1.4 MHz, and aplurality of carriers is available for the 1.4 MHz and a single carrieris available for the 5 MHz in the first wireless communication system,using a time division duplex long term evolution (TD-LTE) as acommunication scheme of the first wireless communication system, whereina communication scheme of the second wireless communication system isdifferent from the TD-LTE, and enabling a wireless communication using 5MHz bandwidth of the first wireless communication system, according to astatus of use of the shared frequency band by the second wirelesscommunication system.

Technical Problem

In the aforementioned common band, when a base station of the TD-LTEmethod uses a relatively wide bandwidth, a system used in anotherwireless communication method may be interfered.

The present disclosure has been made in consideration of theaforementioned problems, and an object thereof is to provide a basestation, a wireless communication system, and a wireless communicationmethod in which effects of interference to a wireless communicationsystem used in another wireless communication system are avoided in acommon band for wireless communication.

Solution to Problem

A base station of the disclosure is a base station of a wirelesscommunication system that commonly uses the same frequency band withanother wireless communication system, wherein the base station uses acarrier of a wide frequency width of own system, in which throughput isimproved in comparison to a carrier having a frequency width of theother wireless communication system when the other wirelesscommunication system does not use the frequency band, and uses a carrierof a narrow frequency width of own system, which is narrower than thefrequency width of the other wireless communication system, when theother wireless communication system uses the frequency band.

Furthermore, the base station of the disclosure is configured toalternately use the carrier of the wide frequency width and the carrierof the narrow frequency width by temporally switching the carrier of thewide frequency width and the carrier of the narrow frequency width whenthe other wireless communication system does not use the frequency band.

In the base station of the disclosure, the other wireless communicationsystem includes a first wireless communication system and a secondwireless communication system having a carrier using a narrowerfrequency width than a frequency width of a carrier in the firstwireless communication system, and the base station uses a carrier of anintermediate frequency width of own system, in which throughput isimproved in comparison to the frequency width of the other wirelesscommunication system when the first wireless communication system doesnot use the frequency band and the second wireless communication systemuses the frequency band, the intermediate frequency width being narrowerthan the wide frequency width.

The base station of the disclosure is configured to alternately use thecarrier of the intermediate frequency width and the carrier of thenarrow frequency width by temporally switching the carrier of theintermediate frequency width and the carrier of the narrow frequencywidth when the first wireless communication system does not use thefrequency band and the second wireless communication system uses thefrequency band.

Furthermore, the base station of the disclosure is configured toinitially use the carrier of the wide frequency width for a short timeand gradually use the carrier of the wide frequency width for a longtime when the carrier of the wide frequency width is used.

A wireless communication method of the present disclosure is a wirelesscommunication method of a wireless communication system that commonlyuses the same frequency band with another wireless communication system,and includes steps of, using a carrier of a wide frequency width of ownsystem, in which throughput is improved in comparison to a frequencywidth of the other wireless communication system when the other wirelesscommunication system does not use the frequency band, and using acarrier of a narrow frequency width of own system, which is narrowerthan the frequency width of the other wireless communication system whenthe other wireless communication system uses the frequency band.

According to the base station, wireless communication system, and thewireless communication method of the disclosure, effects of interferenceto the other wireless communication system are avoided in the commonband for wireless communication.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an operation of wireless communicationaccording to an embodiment of the disclosure.

FIG. 2 is a diagram for explaining a common band according to theembodiment of the disclosure.

FIG. 3 is a diagram for explaining a carrier according to the embodimentof the disclosure.

FIG. 4 is a block diagram of a base station which is an object accordingto the embodiment of the disclosure.

FIG. 5 is a flowchart illustrating an operation example according to theembodiment of the disclosure.

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment of the disclosure is described with referenceto the drawings.

FIG. 1 is a diagram illustrating an operation of wireless communicationaccording to the embodiment of the disclosure. In FIG. 1, a wirelesscommunication system corresponding to a plurality of wirelesscommunication methods is operated, and includes wireless terminals 10 p,10 x, and 10 d, base stations 30 p, 30 x, and 30 d, which correspond tothe respective wireless communication methods, and control devices 20 p,20 x, and 20 d that respectively control the base stations 30 p, 30 x,and 30 d.

For example, the wireless terminal 10 p and the base station 30 pcorrespond to the wireless communication method P, the wireless terminal10 x and the base station 30 x correspond to the wireless communicationmethod X, and the wireless terminal 10 d and the base station 30 dcorrespond to the wireless communication method D.

In the embodiment of the disclosure, it is assumed that the base station30 x exists; however, at least one of the base station 30 p and the basestation 30 d may exist around the base station 30 x or the base station30 p or the base station 30 d may not exist. For example, when awireless network is privately operated, at least one of the base station30 p and the base station 30 d may exist.

FIG. 1 illustrates three types of wireless communication methods;however, the disclosure is not limited to the three types.

These wireless communication methods are operated in a common bandcommonly using the same frequency band. The common band is describedbelow.

FIG. 2 is a diagram for explaining the common band according to theembodiment of the disclosure.

For example, as illustrated in FIG. 2, the common band exists in apublic band which is a frequency band for public use. The common banduses the wireless communication method P, the wireless communicationmethod X, and the wireless communication method D (hereinafter, simplyreferred to as a method P, method X, and a method D respectively). Allthe wireless communication methods are not used in the common band. In afacility such as a hospital and an office, a specific area and the like,one or more wireless communication methods are used; however, all thewireless communication methods may not be used.

Next, a carrier of a frequency width used in the common band isdescribed.

FIG. 3 is a diagram for explaining a carrier according to the embodimentof the disclosure.

In a system using the method D (a first wireless communication system),there are five carriers having a predetermined frequency width in acommon band as illustrated in FIG. 3, and maximum five carriers areused.

In a system using the method X, it is considered to use a TD-LTE method,there are five carriers having a frequency width of 1.4 MHz width in thecommon band as illustrated in FIG. 3, and maximum five carriers areused. As another type, there are two carriers having a frequency widthof 3 MHz width in the common band as illustrated in FIG. 3, and maximumtwo carriers are used. Furthermore, as another type, there is onecarrier having a frequency width of 5 MHz width in the common band asillustrated in FIG. 3.

In a system using the method P (a second wireless communication system),there are 18 carriers having a predetermined frequency width in thecommon band as illustrated in FIG. 3, and maximum 18 carriers are used.

The throughput of a carrier of 1.4 MHz width (a narrow frequency width)of the method X is lower than that of a carrier of the method D, and thethroughput of a carrier of 3 MHz width (a wide frequency width or anintermediate frequency width) and a carrier of 5 MHz width (a widefrequency width) of the method X is higher than that of the carrier ofthe method D. However, since the carrier of 3 MHz width and the carrierof 5 MHz width of the method X may give interference to other wirelesscommunication systems due to a wide band.

Next, the base station according to the embodiment of the disclosure isdescribed.

FIG. 4 is a block diagram of the base station using the method D.

The base station 30 x includes two radio units 31 and 32, a detectionunit 33 related to carrier sensing, a signal processing unit 34 thatprocesses a radio signal, a control unit 35 that controls variousoperations, and a line unit 36 that communicates with a network.

The radio unit 31 performs wireless communication by using the TD-LTEmethod. A reception part of the radio unit 31 outputs a radio signalreceived from the wireless terminal 10 x to the signal processing unit34. A transmission part of the radio unit 31 transmits informationoutputted from the signal processing unit 34 to the wireless terminal 10x as a radio signal.

The radio unit 32, for example, performs carrier sensing duringcommunication of the radio unit 31. A reception part of the radio unit32 outputs a received radio signal to the signal processing unit 34. Atransmission part of the radio unit 32 transmits information outputtedfrom the signal processing unit 34 as a radio signal.

The detection unit 33 detects a carrier from a radio signal, andoutputs, to the control unit 35, carrier sensing information when thecarrier sensing is performed.

The signal processing unit 34 processes the radio signals from thereception parts of the radio unit 31 and the radio unit 32 and outputsobtained information to the control unit 35. Furthermore, the signalprocessing unit 34 outputs information outputted from the control unit35 to the transmission parts of the radio unit 31 and the radio unit 32as a radio signal.

The control unit 35 is configured with a CPU, a memory and the like andcontrols various operations, and the line unit 36 is a network interfacefor communicating with the control device 20 x and the network.

Next, the operation of the control unit 35 of the base station 30 x isdescribed.

As described in FIG. 3, the base station 30 x uses carriers of thefrequency widths of 1.4 MHz, 3 MHz, and 5 MHz; however, when using the 3MHz and 5 MHz carriers, since the carriers are not available in otherwireless communication systems in the common band, the use of the 3 MHzand 5 MHz carriers is limited.

For example, the base station 30 x performs the following operations.

The base station 30 x detects the presence or absence of anotherwireless communication system operating carrier sensing at the start ofcommunication. When the other wireless communication system is detected,the base station 30 x selects an operation for reducing (enablingcoexistence) an influence to the detected other wireless communicationsystem and starts operations.

When another wireless communication system performing carrier sensingduring the operation is further detected, the base station 30 x performsswitching to an operation for reducing an influence to the system andcontinues the operations.

The operation for reducing an influence to the other wirelesscommunication system indicates an operation for reducingpre-interference to the other wireless communication system, and forexample, indicates reducing the number of frequency channels (a wavenumber) used in a current operation, reducing a frequency bandwidth,lowering transmission output, shortening a transmission time (loweringtransmission duty), and the like.

When another wireless communication system is not detected for aprescribed time, the base station 30 x performs an operation forincreasing an influence to another wireless communication system incontrast to the aforementioned operation.

The aforementioned affecting operation is decided in consideration of adetected system, a level when another wireless communication system isdetected, detection frequency and the like.

The operation also includes switching of a plurality of operations. Forexample, switching to a carrier of a wide frequency bandwidth isperformed, an operation is performed for a prescribed time, the carrieris switched to a carrier of a narrow frequency bandwidth, and then theoperation is performed for a prescribed time. Alternatively, itindicates that an operation using a large number of frequency channelsis performed for a prescribed time and then an operation using a smallnumber of frequency channels is performed.

When the base station 30 x switches a plurality of operations, anoperating time of each operation reflects a result of carrier sensing.For example, it indicates that when a non-detection time of anotherwireless communication system in the carrier sensing is long, anoperating time of an operation for increasing an influence to anotherwireless communication system (for example, a frequency bandwidth iswide, the number of frequency channels is large, and the like) isprolonged, but when another wireless communication system is detected,an operation for reducing an influence to the other wirelesscommunication system is prolonged.

When there is a change in the width of a frequency band commonly used,there is also a change in an operation to be selected in the carriersensing. For example, when a frequency width is extended, an operation(for example, an influence to another wireless communication system islarge), which is different from an operation before extension eventhough a system detected in the carrier sensing, a detection level, anddetection frequency are the same, is selected. Furthermore, when afrequency band to be commonly used is reduced, an operation opposite tothe aforementioned operation is performed.

Another wireless communication system means that it is not a systemprivately operated, and a wireless communication method includes boththe same method and different methods.

Next, an example of the operations of the control unit 35 of the basestation 30 x is described using a flowchart. FIG. 5 is a flowchartillustrating an operation example according to the embodiment of thedisclosure.

The control unit 35 performs carrier sensing for a long time (forexample, 24 hours and the like) at the start of wireless communicationand confirms whether carriers of the method D and the method P aredetected (S11).

When the carriers are not detected, the control unit 35 alternately usesa 5 MHz carrier and a 1.4 MHz carrier (S12). For example, in this case,as illustrated in FIG. 3, the control unit 35 operates the 5 MHz carrierfor a prescribed time (for example, 3 hours and the like), switches the5 MHz carrier to the 1.4 MHz carrier, operates the 1.4 MHz carrier for aprescribed time (for example, one hour and the like), operates the 5 MHzcarrier for a prescribed time again, switches the 5 MHz carrier to the1.4 MHz carrier, and then operates the 1.4 MHz carrier for a prescribedtime in a repetitive manner.

When the 5 MHz carrier is used, a communication service with goodthroughput is provided, so that it is possible to prevent interferenceto another wireless communication system.

During the operation, the control unit 35 performs the carrier sensing(S13) and determines whether another wireless communication system isnot detected (S14). When the other wireless communication system is notdetected (Yes in S14), the control unit 35 subsequently performs stepS12.

When the other wireless communication system is detected, the controlunit 35 performs switching to an operation for reducing an influence tothe system and continues the operation. In FIG. 5, when the method P isdetected in step S14, step S22 is performed. When the method D isdetected in step S14, step S31 is performed.

On the other hand, when the method P or the method D is detected in stepS11, the control unit 35 determines whether the method D is not detected(S21).

When the method D is not detected, that is, when the method P isdetected, the control unit 35 alternately uses a 3 MHz carrier and the1.4 MHz carrier (S22). For example, in this case, as illustrated in FIG.3, the control unit 35 operates the 3 MHz carrier for a prescribed time(for example, 3 hours and the like), switches the 3 MHz carrier to the1.4 MHz carrier, operates the 1.4 MHz carrier for a prescribed time (forexample, one hour and the like), operates the 3 MHz carrier for aprescribed time again, switches the 3 MHz carrier to the 1.4 MHzcarrier, and then operates the 1.4 MHz carrier for a prescribed time ina repetitive manner.

When the 3 MHz carrier is used, a communication service with goodthroughput is provided, so that it is possible to prevent interferenceto another wireless communication system.

During the operation, the control unit 35 performs the carrier sensing(S23) and determines whether another wireless communication system isnot detected (S24). When the other wireless communication system is notdetected (Yes in S24), the control unit 35 subsequently performs stepS11.

When the other wireless communication system is detected, the controlunit 35 performs switching to an operation for reducing an influence tothe system and continues the operation. In FIG. 5, when the method P issubsequently detected in step S24, step S22 is performed. When themethod D is detected in step S24, step S31 is performed.

On the other hand, when the method D is detected in step S21, thecontrol unit 35 uses the 1.4 MHz carrier (S31).

During the operation, the control unit 35 performs the carrier sensing(S32) and determines whether another wireless communication system isnot detected (S33). When the other wireless communication system is notdetected (Yes in S33), the control unit 35 subsequently performs stepS11.

When the other wireless communication system is detected, the controlunit 35 performs switching to an operation for reducing an influence tothe system and continues the operation. In FIG. 5, when only the methodP is detected in step S33, step S21 is performed. When the method D issubsequently detected in step S33, step S31 is performed.

As described above, when another wireless communication system is notusing the common band, the base station 30 x uses the 3 MHz or 5 MHzcarrier of own system, in which throughput is improved in comparison toa carrier having a frequency width of the other wireless communicationsystem. When the other wireless communication system is using the commonband, the base station 30 x uses the 1.4 MHz of own system, which has anarrower frequency width than the other wireless communication system.Consequently, it is possible to avoid effects of interference to theother wireless communication system in the common band of the wirelesscommunication and to provide a high speed communication service.

In the above, the control unit 35 operates the 3 MHz or 5 MHz carrierfor a prescribed time, switches the carrier to the 1.4 MHz carrier, andthen operates the 1.4 MHz carrier for a prescribed time; however, inother embodiments, in order to prevent effects of interference toanother wireless communication system, the operating time of the 3 MHzor 5 MHz carrier may be initially shortened, and when the other wirelesscommunication system is detected in the carrier sensing, the operatingtime may be gradually prolonged.

In steps S12 and S22, the 1.4 MHz carrier is alternately used; however,in order to prevent effects of interference to another wirelesscommunication system, when the 1.4 MHz carrier is used, the control unit35 may gradually increase the 1.4 MHz carrier such that the number ofthe 1.4 MHz carriers is initially one, next two, then three, then four,and then five.

In step S12, the 5 MHz carrier is used; however, in order to preventeffects of interference to another wireless communication system, the 3MHz carrier may be initially used, and then the 5 MHz carrier may beused.

Note that the above description is only a specific preferred embodimentfor the purpose of the description and the example of the disclosure.Accordingly, the disclosure is not limited to the aforementionedembodiment and includes many changes and modifications within a rangewithout departing from its essence.

This application is based upon Japanese Patent Application (JapanesePatent Application No. 2015-158698) filed on Aug. 11, 2015, the entirecontents of which are incorporated by citation. Furthermore, allreferences cited herein are incorporated as a whole.

REFERENCE SIGNS LIST

-   10 p, 10 x, 10 d: wireless terminal-   20 p, 20 x, 20 d: control device-   30 p, 30 x, 30 d: base station-   31, 32: radio unit-   33: detection unit-   34: signal processing unit-   35: control unit-   36: line unit

The invention claimed is:
 1. A base station belonging to a firstwireless communication system, comprising: a controller configured toshare the same frequency band with a second wireless communicationsystem, and to use a time division duplex long term evolution (TD-LTE)as a communication scheme of the first wireless communication system; aradio unit configured to perform a carrier sensing; and a detection unitconfigured to detect a carrier from a radio signal received from theradio unit performing the carrier sensing, and output carrier sensinginformation of use of the shared frequency band by the second wirelesscommunication system, wherein a communication scheme of the secondwireless communication system is different from the TD-LTE, thebandwidth of the first wireless communication system has at least 5 MHzand 1.4 MHz, and a plurality of carriers is available for the 1.4 MHzand a single carrier is available for the 5 MHz in the first wirelesscommunication system, and the controller is further configured to enablea wireless communication using 1.4 MHz bandwidth of the first wirelesscommunication system so as not to cause an influence of interference tothe second wireless communication system, according to a result of thecarrier sensing by the radio unit of the status of use of the sharedfrequency band by the second wireless communication system, wherein thecommunication scheme of the second wireless communication system isdifferent from an LTE.
 2. A wireless communication method performed at abase station belonging to a first wireless communication system,comprising: sharing the same frequency band with a second wirelesscommunication system, wherein the bandwidth of the first wirelesscommunication system has at least 5 MHz and 1.4 MHz, and a plurality ofcarriers is available for the 1.4 MHz and a single carrier is availablefor the 5 MHz in the first wireless communication system; using a timedivision duplex long term evolution (TD-LTE) as a communication schemeof the first wireless communication system, wherein a communicationscheme of the second wireless communication system is different from theTD-LTE; performing a carrier sensing; detecting a carrier from a radiosignal received, based on the carrier sensing, and outputting carriersensing information of use of the shared frequency band by the secondwireless communication system; and enabling a wireless communicationusing 1.4 MHz bandwidth of the first wireless communication system so asnot to cause an influence of interference to the second wirelesscommunication system, according to a result of the carrier sensing ofthe status of use of the shared frequency band by the second wirelesscommunication system, wherein the communication scheme of the secondwireless communication system is different from an LTE.
 3. A firstwireless communication system, comprising: a base station configured to:share the same frequency band with a second wireless communicationsystem, wherein the bandwidth of the first wireless communication systemhas at least 5 MHz and 1.4 MHz, and a plurality of carriers is availablefor the 1.4 MHz and a single carrier is available for the 5 MHz in thefirst wireless communication system; use a time division duplex longterm evolution (TD-LTE) as a communication scheme of the first wirelesscommunication system, wherein a communication scheme of the secondwireless communication system is different from the TD-LTE; the basestation further comprising: a radio unit configured to perform a carriersensing; and a detection unit configured to detect a carrier from aradio signal received from the radio unit performing the carriersensing, and output carrier sensing information of use of the sharedfrequency band by the second wireless communication system; and enable awireless communication using 1.4 MHz bandwidth of the first wirelesscommunication system so as not to cause an influence of interference tothe second wireless communication system, according to a result of thecarrier sensing of the status of use of the shared frequency band by thesecond wireless communication system, wherein the communication schemeof the second wireless communication system is different from an LTE. 4.A wireless communication method performed at a base station belonging toa first wireless communication system, comprising: sharing the samefrequency band with a second wireless communication system, wherein thebandwidth of the first wireless communication system has at least 5 MHzand 1.4 MHz, and a plurality of carriers is available for the 1.4 MHzand a single carrier is available for the 5 MHz in the first wirelesscommunication system; using a time division duplex long term evolution(TD-LTE) as a communication scheme of the first wireless communicationsystem, wherein a communication scheme of the second wirelesscommunication system is different from the TD-LTE; performing a carriersensing; detecting a carrier from a radio signal received, based on thecarrier sensing, and outputting carrier sensing information of use ofthe shared frequency band by the second wireless communication system;and enabling a wireless communication using 5 MHz bandwidth of the firstwireless communication system so as not to cause an influence ofinterference to the second wireless communication system, according to aresult of the carrier sensing of the status of use of the sharedfrequency band by the second wireless communication system, wherein thecommunication scheme of the second wireless communication system isdifferent from an LTE.